Method and device for setting the fuse and/or correcting the ignition time of a projectile

ABSTRACT

To avoid mechanical and thermodynamic wear of a programming system, a microwave transmitter, preferably operating in the GHz range, is integrated in the system, while at the same time the advantages of measurement of the muzzle velocity and of a current compensated fuse setting are preserved. The microwave transmitter transmits the current fuse setting, for example, as determined by a fire control computer, to the ammunition, e.g., a projectile. A direct measurement of the actual muzzle velocity itself can be dispensed with, since the real muzzle velocity is determined by the current flight velocity information of the projectile, i.e., it is extrapolated back from this. On the basis of this current projectile velocity, the ignition time, which was preset with the ignition time of the projectile using a standard muzzle velocity, is corrected and used as the current fuse set time.

BACKGROUND OF THE INVENTION

The invention concerns a method and a device for programming a time-fuseprojectile or for correcting an ignition time of a projectile fired froma weapon.

Various time programmings for ammunition are known. The fuses are seteither manually outside the loading chamber before the projectile isfired or electrically in the loading chamber by ignition electronics.The latter type of fuse setting is described, for example, in DE 101 52862 A1.

A method and a device for transmitting information to programmableprojectiles are described in EP 0 992 762 B1.

A method for correcting the preprogrammed triggering of a process in aspin-stabilized projectile and a device for carrying out this method aredescribed in EP 0 992 761 B1.

EP 0 918 209 B1 discloses a projectile with programmable time fuses.

A method and a device for programming time fuses of projectiles are alsodescribed in EP 0 769 673 B1. To compute a disintegration time, apredetermined muzzle velocity of the projectile and a predetermineddistance to a target are used.

DE 38 35 656 A1 discloses a method for correcting the ignition point anda circuit configuration for carrying out this method. The devicemeasures the actual projectile velocity profile with respect to timeonly for a specific period of time after firing. The further velocityprofile of the projectile is then extrapolated. When the distance offlight determined in this way reaches a desired value, the detonation istriggered.

CH 691 143 A5 discloses a device for measuring projectile velocity atthe muzzle of the barrel of a high-cadence cannon. The device has twosensors that are spaced a certain distance apart on a support tube. Thesensors respond to changes in magnetic flux and are connected toevaluation electronics. In this regard, each sensor has a pair of coilsand a closed magnetic circuit. The measured projectile velocity or thefuse set time updated with it is then also supplied as information tothe projectile, generally before the projectile leaves the muzzle area.

Although the above device is distinguished by a high degree of accuracy,it is subject to mechanical and thermodynamic stresses, since themeasuring and programming units are exposed, among other things, to themuzzle gases.

SUMMARY OF THE INVENTION

The object of the invention is to provide a device or an improvedprogramming system that is no longer exposed to mechanical andthermodynamic wear.

Pursuant to this object, and others which will become apparenthereafter, one aspect of the present invention resides in a method forsetting a fuse and/or correcting ignition time of a projectile firedfrom a weapon. The method includes the steps of measuring currentprojectile velocity, computing true muzzle velocity of the projectileduring passage through a cannon tube based on the current projectilevelocity, and adjusting and/or correcting a fuse set time of the fusebased on the computed muzzle velocity.

Another aspect of the invention resides in a device for setting the fuseand/or correcting the ignition of the projectile, which device includesas transmitter/receiver and a fire control system arranged at the weaponand a chip and a timer arranged at the projectile. The chip is connectedto the timer and an output of the timer is connect with a fuse or anignition device of the projectile. It is further possible to provide theprojectile with a computing and/or correction unit. In this case thechip would be connected to the computing and connecting unit and thetimer, while the output of the computing and/or correction unit is alsoconnected to the timer.

The invention is based on the idea of integrating a microwavetransmitter, preferably operating in the GHz range, in the system whileat the same time preserving the advantages of measurement of the muzzlevelocity and of a current compensated fuse setting. This microwavetransmitter transmits the current fuse setting, for example, asdetermined by a fire control computer, to the ammunition, e.g., aprojectile. A direct measurement of the actual muzzle velocity can bedispensed with, since the real muzzle velocity is determined byinformation of the current flight velocity of the projectile, i.e., itis extrapolated back from this. On the basis of this current projectilevelocity, the ignition time, which was preset with the ignition time ofthe projectile using a standard muzzle velocity, is corrected and usedas the current fuse set time.

The flight velocity is measured, for example, by means of the Dopplershift of the transmitting frequencies, preferably at the projectile end.To this end, the transmitting frequency is fixed, and the deviation ismeasured. Since the time that the projectile has been traveling isknown, the current flight velocity can be determined, and, in addition,the real muzzle velocity of the projectile, which the projectile had atthe time it was fired through the muzzle area, can be computed. Thecurrent fuse set time is then determined from this data and madeavailable to the projectile.

If there is a deviation from a preprogrammed standard fuse setting, acorrection is then made in the ammunition or by the fire control system,which then reflects the current fuse set time.

The ammunition or the projectile contains a chip for the programming,for example, an RFID (radio frequency identification) chip (seehttp://de.wikipedia.org/wiki/RFID). This chip has the preferred propertythat it can be supplied with energy by microwave energy.

In addition, an advantage is obtained from the fact that the chip can beprogrammed by the fire control unit with, among other things, thecurrent standard fuse setting and with a correction value or a valuethat is not determined until during the flight of the projectile.

The timer present on the ammunition (or in the ammunition) can then becounted down to zero over the (remaining) flight distance and can thenbring about the desired disintegration before a target.

In addition, the computed muzzle velocity can also be transmitted backif this computation is made in the projectile to allow any deviationsthat may arise to be taken into account in the fire control system.

This system eliminates the previously known expensive measuring andprogramming unit in the cannon or cannon tube. The microwave transmitterthat is used can be locally mounted on the cannon where it is notexposed to either muzzle gases or mechanical stresses. Thetransmitter/receiver is electrically supplied by the electrical systemof the cannon and is supplied with data of the fire control system. Anydata transmitted back from the ammunition can be retransmitted to thefire control system, which can then take it into account.

The invention is explained in greater detail below with reference to thespecific embodiment illustrated in the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

The single FIGURE is a schematic representation of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The sole drawing shows a programming system 1 or a generalized devicefor a time-fuse projectile 2 or a time-fuse piece of ammunition (etc.).

A programmable chip 3, for example, an RFID chip, is located on boardthe projectile 2 and preferably also contains the receiving andtransmitting circuit and memory. A timer 4 present in the projectile 2is also supplied by this chip 3 with the necessary time information onthe spot. Parallel to this, the chip 3 is connected with a computingand/or correction unit 5 if such a unit is provided in the projectile 2.This unit 5 is then also connected with the timer 4. A fuse 6 isfunctionally connected with the output of the timer 4.

The power supply to these units of the projectile 2 can be provided bymicrowave radiation X. Another, preferred possibility is a conventionalpower supply, for example, a battery that can be activated (not shown).

On the cannon or weapon end 10, the programming system 1, which ispreferably mounted on the cannon tube 11, has a transmitter/receiver 12for data transmission to the projectile 2. This transmitter/receiver 12is electrically connected with a fire control system or fire controlcomputer 13 present in the weapon control system.

The programming system operates in the following way:

The current disintegration time, which is computed on the basis of thestandard velocity of the projectile 2, is transmitted to the projectile.The deviation from the standard velocity is determined in the projectileby the Doppler method. On the basis of the deviation, the currentdisintegration time is computed in the projectile 2 or from the cannonend.

If this operation is carried out in the projectile 2 by the computingand/or correction unit 5, then a correction of the fuse set time for thefuse 6 can be performed at the projectile end, in which case the timer 4is supplied with this information. The correction that has been made andthe back-computed muzzle velocity that has been determined can betransmitted via microwave radiation X to the transmitter/receiver 12 onthe cannon 10 and made available to a fire control system (not shown).

On the other hand, if the current projectile velocity is transmitted tothe transmitter/receiver 12 of the cannon 10, and if the correction iscarried out at the cannon end in the fire control system 13, then thedesired value of the fuse time (flight time) based on the true muzzlevelocity of the projectile 2 upon firing is transmitted to theprojectile via the microwave radiation X. This fuse set time iscorrected and used as the new fuse set time in the projectile 2.

Although the present invention ahs been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become more apparent to those skilled in the art. Itis preferred, therefore, that the present invention be limited not bythe specific disclosure herein, but only by the appended claims.

1. A method for setting a fuse and/or correcting ignition time of aprojectile fired from a weapon, comprising the steps of: measuring ofthe current velocity of the projectile; computing true muzzle velocityof the projectile during passage through a cannon tube based on thecurrent projectile velocity; and adjusting and/or correcting a fuse settime of the fuse based on the computed muzzle velocity.
 2. A method inaccordance with claim 1, including measuring the current velocity by theDoppler effect.
 3. A method in accordance with claim 1, whereincomputing true muzzle velocity includes considering current flight time.4. A method in accordance with claim 1, including computing thecorrection of the fuse set time in a computing and/or correction unit inthe projectile.
 5. A method in accordance with claim 1, includingcomputing the correction of the fuse set time at the weapon end in afire control system, and transmitting data between the projectile andthe weapon via microwaves.
 6. A device for setting a fuse and/orcorrecting ignition time of a projectile fired from a weapon,comprising: a transmitter/receiver and a fire control system arranged atthe weapon; and a chip, a computing and/or correction unit and a timerarranged at the projectile, the chip being connected with the computingand/or correction unit and the timer, wherein an output of the computingand/or correction unit is also connected with the timer, an output ofthe timer being connected with a fuse or an ignition device of theprojectile.
 7. A device for setting a fuse and/or correcting ignitiontime of a projectile fired from a weapon, comprising: atransmitter/receiver and a fire control system arranged at the weapon;and a chip and a timer arranged at the projectile, the chip beingconnected with a timer, and an output of the timer being connected witha fuse or an ignition device of the projectile.
 8. A device inaccordance with claim 6, wherein the transmitter/receiver is a microwavetransmitter/receiver that operates in the GHz range.
 9. A device inaccordance with claim 7, wherein the transmitter/receiver is a microwavetransmitter/receiver that operates in the GHz range.
 10. A device inaccordance with claim 6, wherein the chip in the projectile is an RFIDchip.
 11. A device in accordance with claim 7, where the chip in theprojectile is an RFID chip.